1. Field of the Invention
The invention relates to improved electrical devices for numerical measurement and display of the value of a quantity, variations of which are represented by a series of electric pulses, each of which corresponds to an increment of a rational fraction of the unit of measurement of said quantity.
2. Description of the Prior Art
Counter units are known which display the number of pulses counted from the start of counting in decimal notation (counting base equal to 10) or in binary notation (counting base equal to 2.sup.n). These counting units utilize counting circuits connected in cascade.
Some of these units comprise a series of decade counters connected in cascade. Others utilise counting circuits each of which is capable of counting 2.sup.n pulses before supplying a pulse to the counting circuit next following and being returned to zero.
These units are designed so that a new pulse will correspond to a fraction of the measuring unit equal to the reciprocal of the counting base. If in fact b is the counting base and if the unit increase of the magnitude represented by the appearance of a pulse is equal to the fraction 1/b of the measuring unit, each counting circuit is returned to zero and supplies a pulse to the circuit immediately following it when it has counted b pulses.
It may happen that the unitary increment of the quantity to be measured and displayed is smaller than the reciprocal of the counting base. In this case means are known for arranging the counting circuits so that they will have an artifical base smaller than their natural counting base. These means generally consist in suitably modified counting circuits themselves. Thus, certain types of numerical display electric clocks are made in which the artificial counting bases may be 12, 24 or 60.
With known arrangements, however, it is possible to obtain only whole artificial counting bases and such arrangements cannot therefore be adapted to the measurement and display of the value of a quantity the unitary increment of which is a whole fraction of the measuring unit. Furthermore, known arrangements are not designed to enable the user to modify the artificial counting bases.